From: Barry Rowlingson <B.Rowlingson_at_lancaster.ac.uk>

Date: Wed 14 Jun 2006 - 19:57:20 EST

Error in set.seed(-2147483648) : supplied seed is not a valid integer In addition: Warning message:

NAs introduced by coercion

> set.seed(2147483648)

Error in set.seed(2147483648) : supplied seed is not a valid integer In addition: Warning message:

NAs introduced by coercion

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Jun 14 21:17:55 2006

Date: Wed 14 Jun 2006 - 19:57:20 EST

ronggui wrote:

> set.seed is used to set the random number seed.

*> When we use functions ,say runif, to generate random number ,we almost
**> get different set of random number.
*

> As for what the i in set.seed(i) should be,I don't think it is a serious

*> matter.
*

The help for set.seed tells you all you need to know. 'i' must be a single value "interpreted as an integer".

You can give it a decimal number, but it makes it an integer:

> set.seed(pi)

> runif(2)

[1] 0.1680415 0.8075164

> set.seed(3)

> runif(2)

[1] 0.1680415 0.8075164

But not too big an 'integer':

> set.seed(1e100)

Error in set.seed(1e+100) : supplied seed is not a valid integer
In addition: Warning message:

NAs introduced by coercion

because 1e100 isn't represented as an integer internally (in C/Fortran code, its a 'float' or'double precision' type of thing.

For me it takes signed 32 bit integers, so the limits are +/- 2147483647:

> set.seed(2147483647) > set.seed(-2147483647) > set.seed(-2147483648)

Error in set.seed(-2147483648) : supplied seed is not a valid integer In addition: Warning message:

NAs introduced by coercion

> set.seed(2147483648)

Error in set.seed(2147483648) : supplied seed is not a valid integer In addition: Warning message:

NAs introduced by coercion

A 32 bit integer gives you over 4 billion possible random sequences. Is that enough?

Barry

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Wed Jun 14 21:17:55 2006

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